A passively Q-switched diode-pumped Tm:YLF laser with polycrystalline Cr:ZnSe as the saturable absorber is demonstrated for the first time, to the best of our knowledge. By using saturable absorbers with different initial transmission, the maximum pulse energy reached 4.22 mJ with peak power of 162.3 kW for a pulse duration of 26 ns. The maximum output average power amounted to 2.2 W. These results constitute significant improvement from the highest average power, pulse energy and peak power results for the PQS Tm:YLF laser to date.

Passive Q switching of a Tm:YAP solid-state laser at 1935 nm with Cr:ZnSe and Cr:ZnS polycrystalline saturable absorbers is demonstrated for the first time, to the best of our knowledge. With Cr:ZnS, a maximum pulse energy of 1.85 mJ is obtained for a pulse duration of 35.8 ns, resulting in a peak power of 51.7 kW. With Cr:ZnSe, the achieved pulse energy of 1.55 mJ with a pulse duration of 42.2 ns leads to 36.7-kW peak power. These high pulse energies, together with the unique lasing wavelength at 1935 nm, make this laser a promising tool for biomedical and microsurgery applications.

A pulsed high energy and narrow bandwidth tunable Tm:YLF laser at the milli-Joule level is demonstrated. The spectral bandwidth was narrowed down to 0.15 nm FWHM, while 33 nm of tunability range between 1873 nm and 1906 nm was achieved using a pair of YAG Etalons. The laser was actively Q-switched using an acousto-optic modulator and mJ level pulse energy was measured along the whole tuning range at a repetition rate of 1 kHz. Up to 1.97 mJ of energy per pulse was achieved at a pulse duration of 37 ns at a wavelength of 1879 nm, corresponding to a peak-power of 53.2 kW and at a slope efficiency of 36 %. The combination of both high energy pulsed lasing and spectral tunability, while maintaining narrow bandwidth across the whole tunability range, enhances the laser abilities, which could enable new applications in the sensing, medical and material processing fields.

Let W be a finite dimensional purely odd supervector space over C, and let sRep(W ) be the finite symmetric tensor category of finite dimensional superrepresentations of the finite supergroup W . We show that the set of equivalence classes of finite nondegenerate braided tensor categories C containing sRep(W ) as a Lagrangian subcategory is a torsor over the cyclic group Z/16Z. In particular, we obtain that there are 8 non-equivalent such braided tensor categories C which are integral and 8 which are non-integral.